As of July 2011's SDCC, Legendary Pictures and BioWare confirmed the film is still in the works. Casey Hudson and screenwriter Mark Petrosevich were both on Legendary's preview panel.If it was going to happen, it would have been right around now. In time for ME3, when interest in the franchise is at it's peak. It's all downhill for Mass Effect from here (well, from March 6th). If the movie isn't happening now, I'd be willing to bet that it's not happening.When can we expect the movie?
I also don't see why you'd think "it's all downhill from here" for the franchise. Shepard's story may be over after March 6th, but there's no way BioWare won't develop new games in the universe - and of course they will sell well.